package unit5.collection.map;

import java.util.HashMap;

public class MapTest {
    public static void main(String[] args) {
        HashMap hm=new HashMap();
        System.out.println(hm.size());
        hm.put("张三","甲乙");
        hm.put("李二","王五");
        hm.put("小李","一大");
        hm.put("小李","二大");
        System.out.println(hm.size());
        String s=(String)hm.get("小李");
        System.out.println(s);
        hm.put("罗四","王五");
        String w=(String)hm.get("李二");
        System.out.println(w);
        System.out.println(hm.get("罗四"));
    }
}
